A variety of challenges face patients and physicians in the area of drug delivery, for example, ocular drug delivery. In particular, the repetitive nature of the therapies (multiple injections, instilling multiple eye drop regimens per day), the associated costs, and the lack of patient compliance may significantly impact the efficacy of the therapies available, leading to reduction in vision and many times blindness.
Patient compliance in taking the medications, for example, instilling the eye drops, can be erratic, and in some cases, patients may not follow the directed treatment regime. Lack of compliance can include, failure to instill the drops, ineffective technique (instilling less than required), excessive use of the drops (leading to systemic side effects), and use of non-prescribed drops or failure to follow the treatment regime requiring multiple types of drops. Many of the medications may require the patient to instill them up to 4 times a day.
In addition to compliance, the cost of at least some eye drop medications is increasing, leading some patients on limited incomes to be faced with the choice of buying basic necessities or instead getting their prescriptions filled. Many times insurance does not cover the total cost of the prescribed eye drop medication, or in some cases eye drops containing multiple different medications.
Further, in many cases, topically applied medications have a peak ocular effect within about two hours, after which additional applications of the medications should be performed to maintain the therapeutic benefit. In addition, inconsistency in self-administered or ingested medication regimes can result in a suboptimal therapy. PCT Publication WO 06/014434 (Lazar), which is incorporated herein by reference in its entirety, may be relevant to these and/or other issues associated with eye drops.
One promising approach to ocular drug delivery is to place an implant that releases a drug in tissue near the eye. Although this approach can offer some improvement over eye drops, some potential problems of this approach may include implantation of the implant at the desired tissue location, retention of the implant at the desired tissue location, and sustaining release of the drug at the desired therapeutic level for an extended period of time. For example in the case of glaucoma treatment, visits to the treating physician can be months apart, and premature depletion and/or premature release of a drug from an implant can result in insufficient drug being delivered for a portion of the treatment period. This can result in the patient potentially suffering a reduction in vision or blindness.
In light of the above, it would be desirable to provide for the manufacture of improved drug delivery implants that overcome at least some of the above mentioned shortcomings.